Design question

[RhoTu]

I have little knowledge of the various gear formation s so I am looking for someone to point me in the right direction and I will research from that.

My little project is to create a small craddling fixture that will oscillate 80 degrees switch direction then back to center then another 80 degrees further.  I am sure this is simple but I don't know where to start.

TIA

RT

[Steve Fox]

I'm not sure what you are asking, but to make something that will oscillate, you just hinge one side, I think the bottom in your case, and tie a link to the other side, top in your case, and actuate the link. It works kind of like a connectin g rod on a crankshaf t.

You don't really need any gears.  The details depend on how large and how fast.

[RhoTu]

Big bright light bulb goes on!

In the ever effervesc ent words of Lawernce Welk, tank u, tank u, tank u.

[Brian Decker]

Gears for your project would be useful only in so far as you need to regulate the speed of the oscillati on - the rest is just the geometry of the crank system. Maybe you want a full movement 1 time per minute. If your drive motor is 4rpm let's say (I have a ton of old synchrons that are 4rpm) slap a 10T on the motor shaft meshed to a 40T attached to the drive wheel (or crank).  Now the drive is 1rpm.  To get the 80deg movement you just adjust the dimension s of the attachmen t points of the pitman arm on either end and/or it's length and you are there

 Here is a crappy sketch-

[ArtF]

Also, look at the tutorial on 4-bar linkages. You can do that with just two round gears.

Art